无法将类型为'system.Data.DataRowView'的对象强制转换为'System.IConvertible' [英] Unable to cast object of type 'system.Data.DataRowView' to type 'System.IConvertible'

问题描述

在Win Form上我有两个组合框;一个组合框依赖于另一个组合框。

i有这些代码

  private   void  Form2_Load（ object  sender，EventArgs e）
 {
 DataTable dataTable = objProdCat.SelectAll（）; 
 ddlCategory.DataSource = dataTable; 
 ddlCategory.DisplayMember =   ProductCatName; 
 ddlCategory.ValueMember =   ProductCatId; 
} 
  //  下面的另一个cb代码 
  private   void  ddlCategory_SelectedIndexChanged（ object  sender，EventArgs e）
 {
 尝试 
 {
  if （ddlCategory。 SelectedValue！=  null ）
 {
 objProdSubCat.ProductCatId = Convert.ToInt32（ddlCategory.SelectedValue）; 
 BindSubCat（）; 
} 
} 
  catch （例外情况）
 {
 MessageBox.Show（ex.Message） ; 
} 
} 

但问题是它向我展示了这个例外..

如何解决？

无法将'system.Data.DataRowView'类型的对象强制转换为'System.IConvertible'

解决方案

首先提到valuemeber和displaymember绑定数据如下代码

 private void Form2_Load（object sender，EventArgs e）
 {
 ddlCategory.DisplayMember =ProductCatName; 
 ddlCategory.ValueMember =ProductCatId; 
 DataTable dataTable = objProdCat.SelectAll（）; 
 ddlCategory.DataSource = dataTable; 
} 

错误位于以下行

 objProdSubCat.ProductCatId = Convert.ToInt32（ ddlCategory.SelectedValue）; 

将其更改为

 objProdSubCat.ProductCatId = Convert.ToInt32（（（DataRowView）ddlCategory .SelectedValue）[ProductCatId]）; 

参考无法将'System.Data.DataRowView'类型的对象强制转换为'System.IConvertible' [ ^ ]

On a Win Form I have two combo boxes; one combobox is dependent upon another.
i have these code

private void Form2_Load(object sender, EventArgs e)
        {
DataTable dataTable = objProdCat.SelectAll();
ddlCategory.DataSource = dataTable;
ddlCategory.DisplayMember = "ProductCatName";
ddlCategory.ValueMember = "ProductCatId";
        }
//another cb code below
private void ddlCategory_SelectedIndexChanged(object sender, EventArgs e)
        {
            try
            {
                if (ddlCategory.SelectedValue != null)
                {
                    objProdSubCat.ProductCatId = Convert.ToInt32(ddlCategory.SelectedValue);
                    BindSubCat();
                }
            }
            catch (Exception ex)
            {
                MessageBox.Show(ex.Message);
            }
        }

but the problem is it showing me this exception..
how to solve it??
Unable to cast object of type 'system.Data.DataRowView' to type 'System.IConvertible'

解决方案

first mention valuemeber and displaymember the bind datasoure as below code

private void Form2_Load(object sender, EventArgs e)
        {
ddlCategory.DisplayMember = "ProductCatName";
ddlCategory.ValueMember = "ProductCatId";
DataTable dataTable = objProdCat.SelectAll();
ddlCategory.DataSource = dataTable;
        }

Error is on below line

objProdSubCat.ProductCatId = Convert.ToInt32(ddlCategory.SelectedValue);

change it to

objProdSubCat.ProductCatId = Convert.ToInt32(((DataRowView)ddlCategory.SelectedValue)["ProductCatId"]);

refer Unable to cast object of type 'System.Data.DataRowView' to type 'System.IConvertible'[^]

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